During this past year we have made substantial progress on the development of our a collaboratory for microscopic digital anatomy (CMDA). This telemicroscopy system will provide remote access via the intemet to the Resource microscope and high performance computation. This will enable acquisition images and tomographic data, computation for tomographic reconstruction as well as the visualization and analysis of data on three-dimensional structure using a workstation in the researcher's laboratory. Additional funding for this project was obtained in September 1994 from the NSF under the National Challenge challenge program with Mark Ellisman PI, Sid Karin of San Diego Supercomputer Center and Don Greenberg of Cornell University or coPis. NCMIR and SDSC are primarily responsible for the overall system design of the CMDA including task management and network communication, enhancement of functions controlling the microscope, and the development of an improved user interface, while Cornell is focusing on the development of advanced volume and surface rendering methods that will incorporate error metrics and the capability to interactively steer volume data collection. This additional support has also synergized several of related aims of the Resource such as those related to microscope automation. During the past year several components of the CMDA have been implemented. We have completed an initial version of the asynchronous communication environment (ACE) which is designed for transparent distribution of data and messages across the network between the remote users workstation, the microscope control system, and high performance computers. ACE has general utility for other projects requiring flexible distributed processing that involve large datasets using heterogeneous machines. In fact, other groups have already expressed interest in this software and we are currently improving the documentation and performing final debugging to ready the current version of ACE for general distribution within the next few months. ACE will not only be important for remote use of the microscope, but it will also provide a robust method for distributing computationally intensive tasks, such as those required in tomography, for work performed locally in the Resource. We recently demonstrated the CMDA at the Supercomputing 95 conference in San Diego in December 1995 and a paper is in press detailing the components of our current implementation (Young, et al, 1996). The CMDA now incorporates routines developed by NCMIR to automate electron microscope focus and registration as well as the sequential operations required for acquisition of mosaics and tomographic tilt series In addition, the remote user has access to both a high quality surface render and an interactive volume render developed by the Cornell group. Mter some further debugging and improvements to the remote users interface, we expect the present CMDA system to be ready for Beta testing at selected test sites in Illinois, Memphis, and Berkeley. This release will probably employ an ACE interface to tomographic reconstruction routines in the Suprim library. We are working on optimizing both iterative and simple R-weighted tomographic reconstruction on the massively parallel 400 node Paragon computer at the SDSC and designing an ACE interface to this computer. In addition, we are exploring the use of a rapid algorithm for obtaining a preliminary reconstruction developed for the SGI reality engine by Brian Cabral. We expect to provide these reconstruction platforms within this year. The Cornell group is currently improving the interactivity of the 3D visualization programs for the CMDA by using a progressive rendering approach. We are also beginning the design of a resource management system to provide transparent routing of tasks to available and optimal machines for rendering and tomographic reconstruction. A session manager is also under design to control access during sessions on the microscope or for data analysis and computation. Although the current CMDA remote users interface is based on a workstation environment, we are planning, in addition, to develop a WwW interface which would allow remote operation, using a wide variety of machines, including personal computers. Recent developments in WWW such as Java and VRML as well as applications such as the NCSA MR1 remote control system suggest that a practical system for telemicroscopy employing a WWW interface could be developed. We are now considering modifications to the CMDA architcture that would be required for WWW operation.